Dundee United claim the Scottish Football Association is standing in the way of "transparency" after refusing to explain why Paul Paton was found guilty of spitting.

The Tannadice midfielder has been handed a two-match ban following an incident with Jonny Hayes last Saturday - even though the Aberdeen winger backed his claim of innocence.

Paton has not only been told he cannot appeal against the suspension dished out on Thursday - which rules him out of Sunday's clash with Celtic and the Tayside derby against St Johnstone on December 27 - but Hampden chiefs will not even explain how the judicial panel which sentenced him reached its decision.

United argued that under Rule 14.8.3 of the Judicial Panel Protocol - which states: "the tribunal issued a Determination which it could not properly have issued on the facts of the case" - their player should be freed to face the champions this weekend.

But they were told that Rules 13.8.1 and 13.8.2 covering Fast Track Determinations mean they cannot challenge the verdict. Rules 13.11.1 and 13.11.2 also state the player has no right to be told the reasons for the panel's decision.

A Dundee United spokesperson said: "We do feel aggrieved on the basis that firstly we do not believe the player is guilty, secondly the decision cannot be appealed and third the player and club are not allowed to see the basis on which the panel made this judgement.

"Rules that block the ability of players, clubs and supporters to understand such decisions seem at odds with the transparency and openness required in the modern day game. We remain completely supportive of Paul but accept that the matter is now closed. Our focus is now firmly on Sunday's game against Celtic."

Hayes' backing of Paton was posted on Twitter on Tuesday afternoon just an hour before the SFA issued its notice of complaint.

The former Inverness player wrote: ''Just wanna clear it up that Paul Paton never spat at me, what happens and is said on the pitch is brushed aside at the end of 90mins!''

After the charge was announced, Hayes added: ''And What happened on Saturday will stay between myself and Paul, we've spoke on this non issue, and if asked I'll confirm what happened.

''To the Scottish FA, I'd never want to see a fellow pro being accused or found guilty of something that never happened!''

But Tangerines boss Jackie McNamara claims ignoring those tweets highlights just how "flawed" the SFA's disciplinary system is.

"I'm disappointed, angry, frustrated." McNamara told STV. "Derek McInnes phoned us and Jonny Hayes came to the support of Paul to say that he hadn't done it, so you think common sense would prevail.

"To find him guilty of something that he didn't do, I don't know how that's possible. The fact that there's no grounds for appeal, I think it's wrong.

"I think the whole system is wrong. The lad is now tarnished with spitting at someone when he hasn't done it. He's missing three games now for something he hasn't done.

"As a club we're very disappointed and saddened that we can't do anything about it.

"The player is adamant that he didn't do it, and we've looked at the evidence and he clearly didn't do it.

"Had he spat on him we wouldn't condone it. We wouldn't protecting him the way that we are. But as I said, the system is flawed.

"To have a panel with no ex players on it, with people with nothing to do with football, to make that judgement, it's not right."

Paton was also handed his firth booking of the season following the incident, sparked when he fouled Hayes, meaning he will also miss the Dundee derby on New Year's Day.